Stud finder

ABSTRACT

A stud finder for detecting the presence of objects made of ferrous material comprises a base member, a magnet subassembly and a canopy member. The base member has a planar base portion, a sidewall portion upstanding from the planar base portion, and support means formed on the interior of the sidewall portion. The magnet subassembly has a magnet and a sleeve receiving therein at least a portion of the magnet and having mounting portions pivotally mounting the magnet subassembly in the support means with the longitudinal axis extending toward the base portion for pivotal movement relative to the upstanding sidewall portion about an axis parallel to the plane of the base portion. The canopy member is mounted on the upstanding sidewall portion and defines therewith a chamber in which the magnet subassembly is pivotable. The base portion has a pair of side guides in which are formed generally V-shaped notches which are aligned with the pivotal axis of the magnet subassembly and which may be used to mark the workpiece when the longitudinal axis of the magnet subassembly assumes a position normal to the plane of the planar base portion.

United States Patent 1 [111 3,845,384

Stoutenberg et al. Oct. 29, 1974 STUD FINDER made of ferrous material comprises a base member, a [75] Inventors: Carl Christian Stoutenberg, Avon; magnet subassembly and a 'T The bilge Richard H. Rathbun Momvme, member has a planar base portion, a sidewall portion upstanding from the planar base portion, and support both f C nn.

o 0 means formed on the Interior of the sidewall portion.

[ Assigneer The Stanley works, New Britain, The magnet subassembly has a magnet and a sleeve COHH- receiving therein at least a portion of the magnet and [22] Filed: Feb 9 1973 having mounting portions pivotally mounting the magnet subassembly in the support means with the longil PP 331,054 tudinal axis extending toward the base portion for pivotal movement relative to the upstanding sidewall por- 52 us. Cl. 324/41 base 51 Int. Cl G0lr 33/00 P .3? a a jfl g .E g g mg Si ewa portion an e lnest erewi a c am er [58] Field of Search 324/4l, 67, 128/].3, 1.4 in which the magnet subassembly is pivotable The [56] References Cited base portion has a pair of side guides in which are formed generally V-shaped notches which are aligned UNITED STATES PATENTS with the pivotal axis of the magnet subassembly and 2346,77] 4/1944 McBride 8t 324/67 may be used to mark the workpiece when the 2.93.3,679 4/1960 Bray 324/67 longitudinal axis of the magnet subassembly assumes 3 3,293,544 12/1966 Seng 324/41 position normal to the plane of the planar base p tion.

Primary Examiner-Robert J. Corcoran [57] ABSTRACT 10 Claims, 6 Drawing Figures A stud finder for detecting the presence of objects 1 STUD FINDER BACKGROUND OF THE INVENTION Various types of devices have been proposed for Iocating the position of a stud behind a wall surface and the most commonly accepted utilize some form of magnet member which will detect the presence of a ferrous. metal element present on the stud such as nails. screws, clips or even the stud itself when metal studs are employed. Among the various magnetic stud finders are devices wherein the magnet is pivoted in some form of holder such as illustrated in Bray US. Pat. No. 2,933,679 granted on Apr. 19, I960.

Among the disadvantages associated with pivoted stud finders are their susceptibility to being damaged as they are transported in the tool box and their requirement for utilization in a manner so that they may be seen by the user. Even after location of the stud, markin g to record the location is oftentimes difficult or even inaccurate.

Accordingly an object of the present invention is to provide a novel and improved magnetic stud finder which is comprised of relatively few parts and highly durable in use.

Another object is to provide such a stud finder in which the magnet is enclosed within a protective housing and in which the orientation of the magnet subassembly is easily visible from substantially all angles.

A further object is to provide such a stud finder which facilitates the error-free marking of the exact location of the stud by providing convenient marking guides.

It is also an object to provide such a stud finder which is relatively simple and economical to manufacture and assemble.

SUMMARY OF THE INVENTION It has been found that the foregoing related objects can be readily attained in a stud finder comprising a base member. a magnet subassembly and a canopy member. The base member includes a planar base portion. a sidewall portion upstanding from the planar base portion. and support means formed on the interior of the sidewall portion. The magnet subassembly comprises an elongated magnet and a sleeve receiving therein at least a portion of the magnet and having mounting portions pivotally mounting the magnet subassembly in the support means with the longitudinal axis of the magnet subassembly extending toward the base portion for pivotal movement relative to the upstanding sidewall portion about an axis parallel to the plane of the base portion. The canopy member is mounted on the upstanding sidewall portion and defines therewith a chamber in which the magnet subassembly is pivotable.

In a preferred embodiment of the stud finder the sidewall portion is of lesser width than the base portion in the direction ofthe pivotal axis of the magnet to provide side guides. and the side guides have generally V- shaped notches aligned with the pivotal axis and with their apices opposed whereby the V-shaped notches facilitating marking of the workpiece surface when the magnet has its longitudinal axis perpendicular to the plane of the base portion.

In one embodiment. the mounting portions of the magnet subassembly comprise a pair of shaft portions extending outwardly from the sleeve in opposite directions perpendicular to the longitudinal axis of the magnet, the mounting portions having a generally conical configuration adjacent the sleeve and a generally cylindrical configuration at the outer end thereof. Desirably the mounting portions are spaced from the midpoint of the length of the magnet towards the base portion of the base member. The base member has an aperture therein within the area bounded by the sidewall por tions and into which an end portion of the magnet extends, the base being configured to provide a pair of stop members spaced to either side of the pivotal axis of the magnet and extending in the path of pivotal movement, thereby limiting the are through which the magnet subassembly may pivot. The upstanding sidewall portion has a recess extending about the outer periphery of the upper end thereof providing a peripheral shoulder, and the canopy member has a depending lip extending about the outer periphery thereof seated on the shoulder. The support means is opposed recesses formed in the inner periphery of the upper end of the sidewall portion in which the mounting portions are seated, and thus the canopy member overlays the opposed recesses and captures the mounting portions of the magnet subassembly in the support means.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a perspective view of a stud finder embodying the present invention;

FIG. 2 is a side elevational view to an enlarged scale of the stud finder with the housing partially broken away and with the magnet subassembly shown in phantom line in its aligned position;

FIG. 3 is a bottom view thereof to the same scale as FIG. 2;

FIG. 4 is an exploded view of the stud finder to further enlarged scale;

FIG. 5 is a fragmentary sectional view in elevation to a greatly enlarged scale; and

FIG. 6 is a fragmentary sectional view in elevation of the bottom portion of the stud finder to a greatly enlarged scale.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENT Turning now to the attached drawing in detail, therein illustrated is a stud finder embodying the present invention and generally comprised of a base member generally designated by the numeral 10, a canopy member generally designated by the numeral 14 mounted on the base member 10 and defining therewith a chamber II, and a magnet subassembly generally designated by the numeral I2 and pivotally supported within the chamber ll upon the base member If].

The base member 10 has a planar base portion 16 and a sidewall portion 18 of generally rectangular cross section upstanding therefrom with the two portions being cooperatively dimensioned and configured to provide a pair of guide portions 20 on the base portion 16 extending outwardly from opposite sides of the sidewall portion 18. As best seen in FIGS. 4-6, the sidewall portion 18 has its upper end configured to provide a recess 22 extending about the outer periphery thereof and forming a transverse shoulder 23 spaced below the upper edge 24 thereof and a pair of U-shaped notches or recesses 26 on the inner surface thereof on the sides adjacent the guide portions 20, which recesses 26 provide the pivotal support for the magnet subassembly 12. The guide portions have generally V-shaped notches 28 extending inwardly from their edges, the notches 28 being aligned with the pivotal axis defined by the recesses 26 and having their apices opposed. The sidewall portion 18 in turn is provided with a pair of generally vertically extending recesses 30 of generally V-shaped cross section which are aligned with and open into the V-shaped notches 28, and these recesses 30 have their sidewalls diverge and increase in depth towards the base portion 16. In this manner. a pencil or other marking tool (not shown) may be guided into the notches 28 from various angles to facilitate marking of the workpiece surface after the stud finder has been properly oriented.

The base portion 16 has an aperture 32 extending therethrough to the chamber 11 within the confines of the sidewall portion [8 and a pair of upstanding web stop portions 34 extend across the aperture 32 generally parallel to, and spaced to either side of. the pivotal axis defined by the mounting recesses 26. These webs 34 rigidify the structure and provide stops to limit pivoting of the magnet subassembly 12 within the chamber 11.

The magnet subassembly 12 is comprised of the elongated cylindrical bar magnet 40 and a brightly colored sleeve 42 of synthetic resin providing a recess 44 of generally cylindrical configuration dimensioned to receive and snugly seat the bar magnet 40. As best seen in FIG. 4, the sleeve 42 is dimensioned to receive somewhat more than the upper half of the magnet 40, the

lower portion thereof being exposed and extending towards the base portion 16 between the stop portions 34. Projecting from and integrally formed with the body of the sleeve 42 are the pivot arms 46 each comprised of a generally frustoconical portion 46a adjacent the body of the sleeve 42 and generally cylindrical portions 46b at the outer ends which pivotally seat in the U-shaped recesses 26 of the sidewall portion 18. As best seen in FIGS. 5 and 6, the cylindrical portions 46b and recesses 26 are cooperatively dimensioned to provide relatively stable pivotal mounting of the magnet subassembly 12 upon the base member l0. The disposition of the pivot arms 46 at a point spaced below the midpoint of the length of the bar magnet increases the tendency of the magnet subassembly [2 to pivot if it is not directly aligned with the ferrous element being detected. thus facilitating highly accurate alignment.

Seated upon the base member 10 and locking the magnet subassembly 12 in the recesses 26 is the canopy member [4 which is formed of transparent synthetic resin. It has a sidewall portion 50 which tapers upwardly inwardly to a top wall portion 52, and the bot tom edge of the sidewall portion 50 is configured to provide a depending lip 54 extending about the outer periphery thereof and seating in the peripheral recess 22 about the base member 10 with the lower edge thereof firmly against the shoulder 23. The canopy member 14 is secured to the base member 10 by any suitable means such as heat sealing or a separately applied adhesive.

OPERATlON Operation of the stud finder described above is extremely simple and outlined hereinafter. in order to locate a stud hidden behind a wall surface. the planar base portion 16 of the stud finder is placed flush against the surface to be explored and quickly moved therealong until the magnet subassembly [2 begins to pivot, thereby indicating roughly the presence of a ferrous element. The stud finder is then slowly moved about the area until the stud is precisely located as signified by the orientation of the longitudinal axis of the magnet subassembly l2 exactly perpendicular to the plane of said planar base portion and intersecting an imaginary line connecting the apices of the V-shaped notches 28 of the planar base portion 16, as shown by the phantom line position in FIG. 2. The transparent canopy member l4 permits the orientation of the brightly colored sleeve 42 to be discerned whether the stud finder is disposed above or below the level of the user's eye.

A pencil or other marking instrument is then slid along a V-shaped notch 28 or VShaped recess 30 in one side towards the apex of the V-shaped notch 28 at which point a mark is made. Without moving the stud finder, the same procedure is followed on the other side so that when the stud finder is removed from the wall surface, the exact location of the stud may be determined by bisecting a short, straight line between the two marks thus made.

The components of the stud finder of the present invention are especially simple and economical to fabricate and assemble. For the magnet subassembly. the brightly colored plastic sleeve 42 may be separately molded and inserted over a length of the magnet; alternatively the sleeve may actually be molded in situ over a portion of the magnet. if so desired the base member may be fabricated of non-ferrous metal although synthetic resin is preferable. if so desired the assembly may be constructed to permit disassembly by having the canopy member snap fit onto the base member. The lip on the canopy may be formed internally or externally, and the U-shaped recesses providing the pivot seats may be replaced by cylindrical recesses in the inner surface of the sidewall into which the pivot arms are snapped.

During assembly, molded plastic base member may be rested horizontally on its planar base portion and a magnet subassembly inserted thereinto with the exposed end of the magnet resting between the stops of the base portion, and the cylindrical outer ends of the pivot arms resting in the support recesses. Since the magnet subassembly is maintained in position with respect to the base member by means of gravity, the transparent molded plastic canopy member 14 may be easily placed over the magnet subassembly and seated on the base member without any tricky positioning or balancing. The canopy member may then be permanently secured to the base member utilizing conventional techniques such as ultrasonic sealing or adhesive deposition. with the components being maintained in properjuxtaposition during this process through the effect of gravity and, if so desired, the snugness of the lit between the canopy lip and the base member.

Thus, it can be seen from the foregoing description that the stud finder of the present invention is especially easy to assemble and is constructed from a minimum number of components to insure economy of manufacture and durability in use. The marking guide is especially easy to use as the transparent canopy member permits viewing of the orientation of the magnet subassembly from any direction and the beveled V- shaped notches permit easy and error-free marking of the location of the stud even when the marking is done from an awkward angle. Furthermore, the use of the entrapped cylindrical pivot means reduces the possibility of the magnet subassembly becoming dislodged from its proper position under even the roughest of handling.

Having thus described the invention, we claim:

1. A stud finder comprising:

a. a unitary base member including a planar base portion. a sidewall portion upstanding from said planar base portion, and support means formed on the interior of said sidewall portion. said base portion having portions extending laterally outwardly from the base thereof and of the margins of said sidewall portion said laterally outwardly extending portions providing side guide portions with aligning means thereon facilitating marking of the workpiece,

b. a magnet subassembly comprising an elongated magnet and a sleeve receiving therein at least a portion of said magnet and having mounting portions pivotally mounting said magnet subassembly in said support means with the longitudinal axis of said magnet subassembly extending toward said base portion for pivotal movement relative to said upstanding sidewall portion about an axis parallel to the plane of said base portion, said aligning means being aligned with said pivotal axis of said magnet subassembly; and

c. a transparent unitary canopy member mounted on said upstanding sidewall portion and defining therewith a chamber in which said magnet subassembly is pivotable. said transparent canopy member permitting viewing of the orientationof said magnet subassembly.

2. The stud finder of claim 1 wherein said sleeve has a substantially cylindrical configuration and is of lesser length than said magnet.

3. The stud finder of claim 1 wherein said support means comprises a pair of axially aligned surface portions defining a pair of axially aligned recesses on the inner surface of said sidewall portion and said mounting portions comprise a pair of shaft portions extending from said sleeve in opposite directions perpendicular to the longitudinal axis of said magnet. said mounting portions having a generally conical configuration adjacent said sleeve and a generally cylindrical configuration at the outer end thereof seated in said recesses.

4. The stud finder of claim 1 wherein said sidewall portion is of lesser width than said base portion in the direction of the pivotal axis of said magnet to provide said side guides and wherein said aligning means on said side guides are generally V-shaped notches aligned with said pivotal axis and with their apices opposed. said V-shaped notches facilitating marking of the workpiece surface when said magnet has its longitudinal axis perpendicular to the plane of said base portion.

5. The stud finder of claim 1 wherein said base member has an aperture therein within the area bounded by said sidewall portion and into which an end portion of said magnet extends, said base being configured to provide a pair of stop members spaced inwardly from said sidewall portion to either side of said pivotal axis and extending in the path of pivotal movement of said magnet thereby limiting the arc through which said magnet subassembly may pivot.

6. The stud finder of claim 5 wherein said mounting portions of said magnet subassembly are spaced from the midpoint of the length of said magnet towards said base portion of said base member.

7. A stud finder comprising:

a. a unitary base member including a planar base portion, a sidewall portion upstanding from said base portion, and support means comprising the surfaces defining a pair of axially aligned recesses formed in the inner surface of said upstanding sidewall portion;

b. a magnet subassembly comprising an elongated magnet and a sleeve of substantially cylindrical configuration and of lesser length than said magnet receiving therein at least a portion of said magnet and having mounting means comprising a pair of shaft portions extending from said sleeve in opposite directions perpendicular to the longitudinal axis of said magnet and pivotally mounting said magnet subassembly in said pair of axially aligned recesses with the longitudinal axis of said magnet subassembly extending towards said base portion for pivotal movement relative to said upstanding sidewall portion about an axis parallel to the plane of said base portion, said sidewall portion being of lesser width than said base portion in the direction of the pivotal axis of said magnet to provide side guides extending laterally outwardly from the base of said base portion, and wherein said side guides have generally V-shaped notches facilitating marking of the workpiece surface when said magnet has its longitudinal axis perpendicular to the plane of said base portion; and

c. a unitary canopy member formed of transparent synthetic resin and mounted on said upstanding sidewall portion thereby to define therewith a chamber in which said magnet subassembly is pivotable and whereby said pair of shaft portions is captured in said pair of axially aligned recesses and the orientation of said magnet subassembly is visible through said canopy member.

8. The stud finder of claim 7 wherein said upstanding sidewall portion has a recess extending about the outer periphery of the upper end thereof providing a peripheral shoulder and said canopy member has a depending lip extending about the outer periphery thereof seated on said shoulder, said support means being opposed recesses formed in the inner periphery of the upper end of said mounting sidewall portion in which said mounting portions are seated, said canopy member overlying said opposed recesses and capturing said portions of said magnet subassembly in said support means.

9. A stud finder comprising:

a. a unitary base member including a planar base portion. a sidewall portion upstanding from said planar base portion, and support means formed on the interior of said sidewall portion;

b. a magnet subassembly comprising an elongated magnet and a sleeve receiving therein at least a portion of said magnet and having mounting portions pivotally mounting said magnet subassembly in said support means with the longitudinal axis of said magnet subassembly extending toward said base portion for pivotal movement relative to said upstanding sidewall portion about an axis parallel to the plane of said base portion, said base member having an aperture therein within the area bounded by said sidewall portion and into which an end portion of said magnet extends, said base being configured to provide a pair of stop members spaced inwardly from said sidewall portion to either side of said pivotal axis and extending in the path of pivotal movement of said magnet thereby limiting the are through which said pivot; and

. a transparent unitary canopy member mounted on said upstanding sidewall portion and defining therewith a chamber in which said magnet subassembly is pivotable, said transparent canopy memmagnet subassembly may base portion of said base member. 

1. A stud finder comprising: a. a unitary base member including a planar base portion, a sidewall portion upstanding from said planar base portion, and support means formed on the interior of said sidewall portion, said base portion having portions extending laterally outwardly from the base thereof and of the margins of said sidewall portion said laterally outwardly extending portions providing side guide portions with aligning means thereon facilitating marking of the workpiece, b. a magnet subassembly comprising an elongated magnet and a sleeve receiving therein at least a portion of said magnet and having mounting portions pivotally mounting said magnet subassembly in said support means with the longitudinal axis of said magnet subassembly extending toward said base portion for pivotal movement relative to said upstanding sidewall portion about an axis parallel to the plane of said base portion, said aligning means being aligned with said pivotal axis of said magneT subassembly; and c. a transparent unitary canopy member mounted on said upstanding sidewall portion and defining therewith a chamber in which said magnet subassembly is pivotable, said transparent canopy member permitting viewing of the orientation of said magnet subassembly.
 2. The stud finder of claim 1 wherein said sleeve has a substantially cylindrical configuration and is of lesser length than said magnet.
 3. The stud finder of claim 1 wherein said support means comprises a pair of axially aligned surface portions defining a pair of axially aligned recesses on the inner surface of said sidewall portion and said mounting portions comprise a pair of shaft portions extending from said sleeve in opposite directions perpendicular to the longitudinal axis of said magnet, said mounting portions having a generally conical configuration adjacent said sleeve and a generally cylindrical configuration at the outer end thereof seated in said recesses.
 4. The stud finder of claim 1 wherein said sidewall portion is of lesser width than said base portion in the direction of the pivotal axis of said magnet to provide said side guides and wherein said aligning means on said side guides are generally V-shaped notches aligned with said pivotal axis and with their apices opposed, said V-shaped notches facilitating marking of the workpiece surface when said magnet has its longitudinal axis perpendicular to the plane of said base portion.
 5. The stud finder of claim 1 wherein said base member has an aperture therein within the area bounded by said sidewall portion and into which an end portion of said magnet extends, said base being configured to provide a pair of stop members spaced inwardly from said sidewall portion to either side of said pivotal axis and extending in the path of pivotal movement of said magnet thereby limiting the arc through which said magnet subassembly may pivot.
 6. The stud finder of claim 5 wherein said mounting portions of said magnet subassembly are spaced from the midpoint of the length of said magnet towards said base portion of said base member.
 7. A stud finder comprising: a. a unitary base member including a planar base portion, a sidewall portion upstanding from said base portion, and support means comprising the surfaces defining a pair of axially aligned recesses formed in the inner surface of said upstanding sidewall portion; b. a magnet subassembly comprising an elongated magnet and a sleeve of substantially cylindrical configuration and of lesser length than said magnet receiving therein at least a portion of said magnet and having mounting means comprising a pair of shaft portions extending from said sleeve in opposite directions perpendicular to the longitudinal axis of said magnet and pivotally mounting said magnet subassembly in said pair of axially aligned recesses with the longitudinal axis of said magnet subassembly extending towards said base portion for pivotal movement relative to said upstanding sidewall portion about an axis parallel to the plane of said base portion, said sidewall portion being of lesser width than said base portion in the direction of the pivotal axis of said magnet to provide side guides extending laterally outwardly from the base of said base portion, and wherein said side guides have generally V-shaped notches facilitating marking of the workpiece surface when said magnet has its longitudinal axis perpendicular to the plane of said base portion; and c. a unitary canopy member formed of transparent synthetic resin and mounted on said upstanding sidewall portion thereby to define therewith a chamber in which said magnet subassembly is pivotable and whereby said pair of shaft portions is captured in said pair of axially aligned recesses and the orientation of said magnet subassembly is visible through said canopy member.
 8. The stud finder of claim 7 wherein said upstanding sidewall portion has a recess extending about the outer periphery of the upper end thereOf providing a peripheral shoulder and said canopy member has a depending lip extending about the outer periphery thereof seated on said shoulder, said support means being opposed recesses formed in the inner periphery of the upper end of said mounting sidewall portion in which said mounting portions are seated, said canopy member overlying said opposed recesses and capturing said portions of said magnet subassembly in said support means.
 9. A stud finder comprising: a. a unitary base member including a planar base portion, a sidewall portion upstanding from said planar base portion, and support means formed on the interior of said sidewall portion; b. a magnet subassembly comprising an elongated magnet and a sleeve receiving therein at least a portion of said magnet and having mounting portions pivotally mounting said magnet subassembly in said support means with the longitudinal axis of said magnet subassembly extending toward said base portion for pivotal movement relative to said upstanding sidewall portion about an axis parallel to the plane of said base portion, said base member having an aperture therein within the area bounded by said sidewall portion and into which an end portion of said magnet extends, said base being configured to provide a pair of stop members spaced inwardly from said sidewall portion to either side of said pivotal axis and extending in the path of pivotal movement of said magnet thereby limiting the arc through which said magnet subassembly may pivot; and c. a transparent unitary canopy member mounted on said upstanding sidewall portion and defining therewith a chamber in which said magnet subassembly is pivotable, said transparent canopy member permitting viewing of the orientation of said magnet subassembly.
 10. The stud finder of claim 9 wherein said sleeve has a substantially cylindrical configuration and is of lesser length than said magnet and wherein said mounting portions of said magnet subassembly are spaced from the midpoint of the length of said magnet towards said base portion of said base member. 